/Engine/Source/Runtime/Slate/Public/Widgets/Views/STreeView.h
Deprecated* SetItemsSource is deprecated. You probably want to use SetTreeItemsSource.
void SetItemsSource ( [TUniquePtr](API\Runtime\Core\Templates\TUniquePtr)< [UE::Slate::ItemsSource::IItemsSource](API\Runtime\Slate\Widgets\Views\IItemsSource)< ItemType >> Provider )